Syringe holders

ABSTRACT

A syringe holder is designed to be thrown away after a single use with the syringe safely captive within. The holder has a barrel ( 5 ) into whose rear end a syringe ( 1 ) is entered until the rear flange ( 2 ) of the syringe seats in a socket ( 15 ). Then a gate ( 16 ) is hinged in a radial plane through a slot ( 14 ) in a thick flange ( 12 ) surrounding the socket ( 15 ) and snap fastens in a position obstructing rearward movement of the syringe ( 1 ). The syringe needle ( 3 ) projects forwardly of the barrel ( 5 ) and is shrouded by a sleeve ( 7 ) captive to the barrel and urged forwards by a spring ( 6 ). The sleeve ( 7 ) retracts to expose the needle during injection but afterwards, having moved forwards again, it can be rotated to snap fasten to the barrel ( 5 ) and be locked in its needle shrouding position. The sleeve ( 7 ) can also be adapted to remove a cap or sheath from the needle ( 3 ) when, before injection, it is moved backwards and then forwards.

[0001] This invention relates to syringe holders.

[0002] The syringe to be used with these holders will be of the usualform, with a cylindrical capsule containing the dose, which is captiveby a plunger whose rod extends clear of the rear end of the capsule.That rear end has a radially projecting flange, usually annular with twoflats, while a needle projects axially from the reduced forward end. Aprotective cap is generally provided to shield the needle before use.Such a syringe will be referred to as of the kind described.

[0003] Such syringes can be used by themselves, but they are small and“fiddly”, and control is not easy. Also the exposed needle is dangerousand after use it is important to make it safe. Replacing the cap is notan answer, since it can easily be removed again.

[0004] Therefore devices have been developed to contain the syringe andto make it easier to use and to render it safe after use. Some of theseare quite complex, with trigger release of a spring firing mechanism,and automatic spring retraction to bring the needle back into a housing.But they are not disposable items, or at least they are rather expensiveto throw away after a single use, and they need to be carefully unloadedof their syringes.

[0005] The aim of this invention is to provide a basic throwaway holder,which is easy to load with a syringe, which makes the syringe securewhen loaded, and which preferably also offers a simple and reliable wayof irreversibly shrouding the needle after use.

[0006] According to the present invention there is provided a syringeholder comprising a barrel with an open rear end to receive a syringe ofthe kind described, said rear end having means engageable behind theflange at the rear end of the capsule once the syringe reaches its fullyhoused position, thereby to hold the capsule within the barrel,characterised in that the rear end of the barrel has a socket to receiveand locate said flange and a gate that hinges in a radial plane from anon-obstructing position clear of the socket to an obstructing positionpreventing escape of the capsule flange from the socket but not impedingoperation of the plunger, the gate being captive in said obstructingposition.

[0007] The gate may be integrally moulded with the barrel and connectthereto by a thin web which acts as its hinge.

[0008] Preferably, the gate hinges through a slot to intrude into thesocket, snap fastening therein as it reaches said obstructing position.

[0009] Additionally, a spring inside the barrel can surround the capsuleof the syringe to act on a protective sleeve captive to but slidablyengaged with the forward end of the barrel. This will urge the sleeveforwards to shroud the needle before and after use, but allow the sleeveto retract and expose the needle during the injection.

[0010] The engagement of the sleeve and barrel may permit mutualrotation about their common axis from a free sliding condition to anirreversibly locked condition when the sleeve is in its forward needleshrouding position. In this case the barrel conveniently has aprojection that moves within an L-shaped slot in the sleeve, the longarm of the slot being longitudinal of the sleeve and the short armcircumferential towards its rear end. The co-operating cylindricalsurfaces of the barrel and sleeve may have tooth-profiled splines thatcan snap past each other when the mutual rotation moves the projectioninto the short arm of the slot. The projection is thereby trapped andaxial movement is prevented.

[0011] Alternatively, or in addition, the projection may have anirreversible snap-in engagement with the short arm of the slot.

[0012] The sleeve may also have another function, being equippedinternally with integral spring tabs angled to be pulled back past thebase of a needle cap or sheath, but then flexing inwards so that, whenthe sleeve is urged forwards again, the tabs push the cap or sheath offthe needle while the sleeve assumes its needle-protecting position.

[0013] For a better understanding of the invention, one embodiment willnow be described, by way of example, with reference to the accompanyingdrawings, in which:

[0014]FIG. 1 is a side view of a medical syringe,

[0015]FIG. 2 is a perspective view of a syringe holder,

[0016]FIG. 3 is a side view of part of a barrel of the syringe holder,

[0017]FIG. 4 is a section on the line IV-IV of FIG. 3,

[0018]FIG. 5 is a side view, partly in ghost, of a needle protectorsleeve of the syringe holder, and

[0019]FIG. 6 is an end view of the sleeve, in the direction A of FIG. 5.

[0020] The syringe to be used in the holder is of the usual form, havinga capsule 1 with an outward radial flange 2 at its rear end. A needle 3,initially with a cap shown in outline, projects from its forward end,and a plunger 4 projecting from the rear end is urged forwards in use toexpress a dose within the capsule through the needle 3.

[0021] The holder has three main components, namely a barrel 5, ahelical spring 6 within the barrel, and a needle protection sleeve 7which telescopes over the forward end of the barrel.

[0022] The barrel 5 is straight cylindrical over most of its length. Atits forward end there are two diametrically opposed external splines 8of right-angled triangular cross-section, aligned parallel with the axisof the barrel, and with one side radial to the barrel and the otheralmost tangential thereto. Both radial sides face in the samecircumferential direction. Midway between these splines 8 on the outersurface of the barrel and set back a bit from the end is a shallowsquare projection 9.

[0023] About two thirds the length of the barrel back from its forwardend there is a generally elliptical external flange 10, for ease ofhandling the device in use.

[0024] The barrel has an asymmetric cup formation 11 at its rear end toreceive and locate the rear end of the syringe. A flange 12 is thick andis extended radially over an arc of about 90° by a curved loop 13.Opposite this, a slot 14 is provided between the upper and lower facesof the flange 12, open to the socket 15 in which the flange 2 of thesyringe seats. When that is properly in position, the rear face of theflange 2 is just beyond the slot 14 in the forwards direction. A gate 16is hinged by a thin web 17 to the side of the flange 12 and 90 from thecrown of the loop 13 and can be swung from the retracted position shownto enter and become captive in the slot 14, at the same time making thesyringe captive in the barrel 5. The gate is generally D-shaped with thehinge at one corner, but the straight part of the D has a semicircularcut-out 18 which allows it to half-surround the plunger 4 while theadjacent part of the body of the gate overlies the flange 2 and blocksrearward movement of the syringe.

[0025] The gate 16 snap fastens in the slot 14. It is largely of athickness equal to the width of the slot 14, but around the crown of thecut-out 18 there is a correspondingly curved ramp 19 ending in a step 20back to the main body of the gate. As that is closed, the ramp wedgesthe slot 14 a bit wider, but once the step 20 reaches the socket 15 theslot 14 closes against the gate and that is secure.

[0026] Beyond the ramp 19 from the cut-out 18 there is a curved slot 21,and beyond that the gate steps out into a thicker section 22 with a loop23 so that, when closed, there is a match with the diametricallyopposite loop 13.

[0027] The needle protector sleeve 7 is a cylindrical member reducing ata shoulder 24 forward of its mid-length. Both the larger and the reduceddiameter portions 25 and 26 have external ribs 27 for a good grip.Internally, there are tabs 28 projecting inwardly and forwardly from theshoulder 24, which is stepped on the inside rather than sloping as onthe outside. The larger diameter portion 25 has an L-shaped slot 29 withthe long arm extending over most of its length, and the short arm beingpart circumferential at the rear end. The basic width corresponds tothat of the projection 9, and at the entrance to the short arm there aresmall lugs 30 which make for a snap action entry of the projection 9into that part of the slot. Two diametrically opposed splines 31 areformed internally of the larger diameter portion 25 and are positionedto co-operate with the splines 8 when the projection 9 enters the shortarm of the slot 29.

[0028] The device is assembled by inserting the spring 6 into theforward end of the barrel 5 and then pressing that forward end into therear portion of the protector sleeve 7 with the projection 9 alignedwith the long arm of the slot 29. There is enough flexibility andresilience for this to be a snap action, and to ease the fitting thereis a shallow longitudinal channel 32 on the inside of the sleeve fromits rear end to the slot 29 to accommodate the projection 9 to someextent, although it will still have to be forced through. Once theprojection 9 is in the slot 29 the two members 5 and 7 are mutuallycaptive. The holder is then ready to receive the syringe, which isentered into the rear of the barrel 5 until its flange 2 seats in thesocket 15, to be trapped as described.

[0029] Prior to use, the protector sleeve 7 is moved rearwardly againstthe spring 6, which bears on the inner step in the shoulder 24, untilthe tabs 28 snap past the enlarged rear end of the needle cap. When thesleeve 7 is let go, it is moved forwards again by the spring 6 and thetabs 28 ease the needle cap off. But when that cap is removed the tip ofthe needle 3 remains shrouded by the reduced diameter portion 26. Thedevice is now ready to use.

[0030] The forward end of the sleeve 7 is applied to the patient's skinand pressure is exerted. The needle 3 penetrates as the sleeve 7 ispushed back. The amount the needle 3 projects is dependent on the lengthof the portion 26 of the sleeve 7 and the stop provided by the outerstep in the shoulder 24, up against which the end of the barrel 5 comes.The projection 9 meets the forward end of the slot 29 at the same time.The spring 6, whose forward end abuts the inner step in the shoulder 24,is compressed. The plunger 4 is then pressed to eject the dose throughthe needle 3.

[0031] On withdrawal, the spring 6 exerts itself and pushes the sleeve 7forwards so that the needle 3 is shrouded.

[0032] The sleeve 7 is then pulled right forwards, if not already movedthere by spring action, and twisted so that the projection 9 enters theshort arm of the slot 29. As it seats, the splines 8 and 18 snap pasteach other, capturing the sleeve 7 in that position. So the needle 3 isnot re-exposable, and the device is safe for disposal.

[0033] The snap action of the splines 8 and 18 is more positive thanthat of the projection 9 past the lugs 30, which could be omitted.Alternatively or in addition they could be made non-return in relationto the projection 9, rendering the splines 8 and 18 redundant orcomplementing those splines.

1. A syringe holder comprising a barrel with an open rear end to receivea syringe of the kind described, said rear end having means engageablebehind the flange at the rear end of the capsule once the syringereaches its fully housed position, thereby to hold the capsule withinthe barrel, characterised in that the rear end of the barrel has asocket to receive and locate said flange and a gate that hinges in aradial plane from a non-obstructing position clear of the socket to anobstructing position preventing escape of the capsule flange from thesocket but not impeding operation of the plunger, the gate being captivein said obstructing position.
 2. A syringe holder as claimed in claim 1,characterised in that the gate is integrally moulded with the barrel andconnects thereto by a thin web which acts as its hinge.
 3. A syringeholder as claimed in claims 1 or 2, characterised in that the gatehinges through a slot to intrude into the socket, snap fastening thereinas it reaches said obstructing position.
 4. A syringe holder as claimedin claim 1, 2 or 3, characterised in that a spring inside the barrelsurrounds the capsule of the syringe to act on a protective sleevecaptive to but slidably engaged with the forward end of the barrel, thisurging the sleeve forwards to shroud the needle before and after use,but allowing the sleeve to retract and expose the needle during theinjection.
 5. A syringe holder as claimed in claim 4, characterised inthat the engagement of the sleeve and barrel permits mutual rotationabout their common axis from a free sliding condition to an irreversiblylocked condition when the sleeve is in its forward needle shroudingposition.
 6. A syringe holder as claimed in claim 5, wherein the barrelhas a projection that moves within an L-shaped slot in the sleeve, thelong arm of the slot being longitudinal of the sleeve and the short armcircumferential towards its rear end.
 7. A syringe holder as claimed inclaim 6, characterised in that co-operating cylindrical surfaces of thebarrel and sleeve have tooth-profiled splines that can snap past eachother when the mutual rotation moves the projection into the short armof the slot, the projection thereby being trapped and axial movementprevented.
 8. A syringe holder as claimed in claim 6 or 7, characterizedin that the projection has an irreversible snap-in engagement with theshort arm of the slot.
 9. A syringe holder as claimed in any one ofclaims 4 to 8, wherein the sleeve is equipped internally with integralspring tabs angled to be pulled back past the base of a needle cap orsheath, but then flexing inwards so that, when the sleeve is urgedforwards again, the tabs push the cap or sheath off the needle while thesleeve assumes its needle-protecting position.